1. Field of the Invention
This invention pertains to transparent domes for use in missiles, and more particularly to such domes which retain their transmissivity and structural integrity under high aerodynamic loads.
2. Description of the Prior Art
Transparent domes used in missiles serve to shield energy responsive instrumentation from aerodynamic loads while transmitting radiant energy in preselected wavelengths. In missiles which attain supersonic velocity, the transparent dome must be able to survive aerothermodynamic heating. State of the art materials, such as IRTRAN, crack when subjected to supersonic environments because of thermally induced stresses which develop in the material. Those materials which are able to survive a supersonic environment are generally expensive and limit the window of available frequencies which may be transmitted.
Solid crystal domes, when damaged by thermal stresses or aerodynamic pressure, experience catastrophic failure once the structural integrity of the dome shape is damaged. Failure of the protective dome in a supersonic missile rapidly leads to destruction of the guidance sensor mechanism or other instrumentation normally protected by the dome, and thus destroys the guidance capability of the missile.